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7700 MultiFrame Manual
7735AVC-LB Video Composite Encoder and Audio DAC with SoftSwitch
6.3.
CALIBRATE AUDIO MONO DETECTION
1. Supply the card with a stereo signal that originated from mono material and that has a large amount of
uncorrelated noise added to each channel. This will allow the user to set the Mono Threshold to a
value that will detect the mono condition in the presence of noise.
Make sure that the material is in-phase. Mono material will not be detected if it is
out of phase.
2. Turn off all sources of errors in a Fault Condition and assign Mono as the only error. Also, make sure
that the Fault Duration is set to a small number of frames in order to see when the error condition
disappears.
3. Set the Mono Duration to 0.5 sec to view the results of adjusting the Mono Threshold Level without
getting confused by the detection time.
4. Adjust the Mono Threshold Level so that the Fault Condition detects the mono material in the
presence of noise.
5. Set the Mono Duration to a time period appropriate to the application.
Periods of silence (below the Silence Level) will extend this duration. In other
words, periods without audio content are not included in the mono detection.
Stereo material with long periods of similar left/right content (i.e. talking heads
in a news cast) may cause the mono detector to fire. It is best to set the Mono
Duration to a value larger than what the user would expect.
6.4.
DEFINE THE AUDIO FAULT CONDITION(S)
1. A Fault Condition is defined as a group of one or more problems grouped together that will create a
fault when any one of the problems exist. Decide what grouping of error conditions will generate a fault
by setting the appropriate condition to Yes in the Fault Condition menu.
2. Set the Fault Duration to either Until Reset or to a time value. This is how long the condition will stay
active after the conditions generating the fault go away.
3. Configure a Fault Message. Enter the text to display on screen, its H and V position, and its
characteristics (opacity, colour, etc).
4. Assign the Fault Condition to an output contact closure (GPO) if it is desired.
7735AVC-LB - 14
Revision 1.6
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